MP Board Class 11th Physics Important Questions Chapter 1 Physical World

Physical World Class 11 Important Questions Very Short Answer Type

Question 1.
Define science.
Answer:
The systematic knowledge based on observation, experiment and scientific logic, is called science.

Question 2.
Define physics.
Answer:
Physics is that branch of science in which matter, energy and their interactions are studied.

Question 3.
What are the different branches in which physics is divided?
Answer:

  1. Classical physics : All the discoveries before 1900 A.D. is included in it. It deals with mechanics, light, heat, sound, electricity and magnetism.
  2. Modern physics: All the discoveries after 1900 A.D. is included in it. It deals with electron, molecule, nucleus, quantum mechanics etc.

MP Board Class 11th Physics Important Questions Chapter 1 Physical World

Question 4.
Name any four physicists and their discoveries.
Answer:

Physicists Discovery
1. Sir C.V. Raman Raman effect
2. Homi J. Bhabha Cosmic rays
3. Satyendranath Bose Wireless
4. Meghnath Saha Theory of thermal-ionization.

Question 5
Name two devices used in daily life and their working principle.
Answer:

Device Principle
1. Aeroplane Bernoulli’s theorem
2. Radio and television Propagation of e

Question 6.
What are the different branches of science?
Answer:
The different branches of science are Physics, Chemistry, Biology, Botony, Maths, Medical science etc.

Question 7.
What do you mean by matter?
Answer:
The substance which occupy space is called matter. It has mass for example : Stone, Iron etc.

Question 8.
What do you mean by energy?
Answer:
Capacity of doing work is called energy. Without energy no work can be perform.

MP Board Class 11th Physics Important Questions Chapter 1 Physical World

Question 9.
What are different forms of energy?
Answer:
The different forms of energy are: Mechanical energy, Heat energy, Light energy, Electrical energy, Chemical energy, Nuclear energy etc.

Question 10.
Name any three recent inventions in physics.
Answer:
The recent inventions are LASER, Computer and Super conductivity.

Question 11.
Which scientist discovered Mass-energy relation?
Answer:
Mass-energy relation E = mc2 was discovered by Einstein.

Question 12.
Write the name of the force which is always attractive?
Answer:
Gravitational force.

Question 13.
Write the following forces in order of their increasing magnitude. Electromagnetic force, Nuclear force, Gravitational force.
Answer:
Gravitational force, Electromagnetic force and Nuclear force.

Question 14.
Write the name of that strong force which is responsible for stability of nucleus.
Answer:
Nuclear force.

MP Board Class 11th Physics Important Questions Chapter 1 Physical World

Question 15.
What is the range of weakest force?
Answer:
10-16m.

Question 16.
Write the name of the field-produce due to :
(i) Static charge,
(ii) Moving charge.
Answer:
(i) Static charge : Only electrical field.
(ii) Moving charge : Magnetic field.

Physical World Class 11 Important Questions Short Answer Type

Question 1.
What do you mean by systematic observation?
Answer:
Systematic observations: To work out on a problem, the scientists collected all relevant data concern to the problem, by systematic experiments and observations.

Question 2.
How hypothesis is formulated?
Answer:
Formulation of hypothesis: On the basis of observations working law is formed called hypothesis.

Question 3.
How hypothesis is tested?
Answer:
Testing of hypothesis: On the basis of hypothesis and predictions, conclusions are drawn and it is verified by new experiments. This is called testing of hypothesis.

Question 4.
How theory is established?
Answer:
Final theory: If the conclusions and predictions are verified by the experiments, then the hypothesis is accepted as final theory, otherwise corrections are made and verified again. The phenomena are repeated till the final theory is achieved.

Question 5.
What is theory? When does it need modification? Explain it with one example.
Answer:
The hypothesis, tested by experiments is called theory.
Sometimes a new measurement shows difference between the existing theory and observations then it needs to be modified.
Example: Huygens thought that light waves are longitudinal in nature. But polarization of light could not be explained on the basis of this thought. Therefore, Fresnel assumed that the light waves are transverse in nature.

MP Board Class 11th Physics Important Questions Chapter 1 Physical World

Question 6.
Why physics is called as basic science?
Answer:
Physics is called basic science because its seek out and understand the basic laws of nature upon which all physical phenomenon is depended. It has brought to us deeper and deeper levels of understanding nature.

Question 7.
What is scientific method? Explain the steps of scientific method.
Answer:
Scientific method: The methods by which a scientist works to establish theories
and laws are called scientific method.
The steps of scientific method are :

  • Systematic observations,
  • Formulation of hypothesis,
  • Testing of hypothesis,
  • Final theory.

Physical World Class 11 Important Questions Long Answer Type

Question 1.
What is the relation of physics to other branches of science?
Answer:
The different branches of science in relation to physics are given below :
1. Physics in relation to Mathematics:
The knowledge of mathematics is necessary to understand the laws and theories of physics which is a powerful tool. Without mathematics expansion of physics is impossible. Radio, television, computer, satellite, telecommunication etc. are the result of combined applications of physics and mathematics.

2. Physics in relation to chemistry:
Physics plays an important role in the development of chemistry. The structure of atoms described by physics, the arrangement of atoms in periodic table, the nature of valence electrons and chemical bonds. The X-rays and neutron diffractions are the results of research in physics.

3. Physics in relation to biological science :
The technology of physics are used in Biology. The optical microscopes developed by physics are extensively used in biological science. The electron microscopes which is nearly a million times powerful than optical microscopes used in the study of the structure of the cells with the help of X-rays position of bone fracture is found and also the presence of foreign materials hidden in the body. X-rays are also used in the treatment of cancer.

Question 2.
Explain the influence of Physics on the society.
Answer:
The Physics has influenced the society in two ways:
(i) Living standard :
Physics has developed the technology and hence the inventions of machines, devices and instruments give comfort and protection to human life.
By the television and radio transmission, has made possible to see the happenings live from any part of the world. Computer can calculate very complicated calculations within no time. Thus, the efficiency of men have increased.

(ii) Effect on the thinking of human beings: The contribution of Physics in the field of education, medical sciences etc., developed the scientific aspect and therefore the narrow thinking of caste and creed, religion and superstitions are removed from the society.

MP Board Class 11th Physics Important Questions Chapter 1 Physical World

Question 3.
Name few scientists and their contribution ¡n physics.
Answer:
Scientists and their contribution in physics:

Scientists Discovery
1. Sir Isaac Newton Laws of motion
2. Albert Einstein Theory of relativity
3. James Chadwick Discovery of neutron
4. H. A. Becquerel Radioactivity
5. SirC.V.Raman Raman effect
6. Homi J. Bhabha Cosmic rays
7. Satyendranath Bose Wireless
8. MeghnathSaha Theory of thermal-ionization.

Physical World Class 11 Important Questions Objective Type

1. Multiple- choice questions:

Question 1.
Which among the following is called basic science :
(a) Physics
(b) Chemistry
(c) Maths
(d) Biology
Answer:
(a) Physics

Question 2.
The oldest branch of physics is :
(a)Thermodynamics
(b) Optics
(c) Mechanics
(d) Sound.
Answer:
(c) Mechanics

Question 3.
The weakest force of the nature is :
(a) Electrical force
(b) Magnetic force
(c) Nuclear force
(d) Gravitational force.
Answer:
(d) Gravitational force.

Question 4.
Rocket propulsion is based on the law :
(a) Faraday’s law
(b) Newton’s law
(c) Galileo’s law
(d) Bernoulli ‘s theorem.
Answer:
(b) Newton’s law

Question 5.
Working principle of aeroplane is based on …………………….:
(a) Laws-of thermodynamics
(b) Faraday’s laws of electromagnetic induction
(c) Bernoulli’s theorem
(d) Newton’s laws of motion.
Answer:
(c) Bernoulli’s theorem

MP Board Class 11th Physics Important Questions Chapter 1 Physical World

Question 6.
Quantum mechanics was discovered by the scientist:
(a) Michael Faraday
(b) Chandrashekhar Venkat Raman
(c) Satyendranath Bose
(d) Somnath Saha.
Answer:
(c) Satyendranath Bose

Question 7.
Planetory laws of motion was propounded by :
(a) Max-plank
(b) Newton
(c) Kepler
(d) Faraday.
Answer:
(c) Kepler

Question 8.
Who gave the electromagnetic theory of waves :
(a) Niel-Bohr
(b) James dark Maxwell
(c) Michael Faraday
(d) Johans kepler.
Answer:
(c) Michael Faraday

2. Fill in the blanks:

1. Theory of relativity was given by ……………..
Answer:
Albert Einstein

2. Neutron was discovered by…………………..
Answer:
James Chadwick

3. Abdus Salam is from the country ………………….
Answer:
Pakistan

MP Board Class 11th Physics Important Questions Chapter 1 Physical World

4. Computer is based on the principle of ………………….
Answer:
Digital logic of electronic circuit

5. Sir Issac Newton belonged to the country …………………
Answer:
England

3. Match the following:
I.

Column‘A’ Column‘B’
1. Newton (a) Principle of electromagnetic waves
2. Einstein (b) Cosmic ray
3. Maxwell (c) Dual nature of light
4. de Broglie (d) Scattering of light
5. Sir C. V. Raman (e) Laws of gravitation.
6. H. J. Bhabha (f) Explanation of photoelectric effect.

Answer:
1. (e) Laws of gravitation.
2. (f) Explanation of photoelectric effect
3 (a) Principle of electromagnetic waves
4 (c) Dual nature of light
5 (d) Scattering of light
6. (b) Cosmic ray

II.

Column ‘A’ Column ‘B’
1. Hydroelectric power (a) Laws of motion
2. Aeroplane (b) Propogation of electromagnetic waves
3. Electric generator (c) Conversion of gravitational energy into electrical energy
4. Rocket propulsion (d) Digital logic of electronic circuits
5. Television (e) Faraday’s laws of electromagnetic induction
6. Computer (f) Bernoulli’s

Answer:
1. (c) Conversion of gravitational energy into electrical energy
2. (f) Bernoulli’s principle.
3. (e) Faraday’s laws of electromagnetic induction
4. (a) Laws of motion
5. (b) Propogation of electromagnetic waves
6. (d) Digital logic of electronic circuits

MP Board Class 11th Physics Important Questions Chapter 1 Physical World

III.

Column ‘A’ Column ‘B’
1. Sir Isaac Newton (a) Scotland
2. Galileo (b) Germany
3. Albert Einstein (c) India
4. Clark Maxwell (d) Italy
5. Archimedes (e) England
6. H. J. Bhabha (f) Greece.

Answer:
1. (e) England
2. (d) Italy
3. (b) Germany
4. (a) Scotland
5. (f) Greece.
6. (c) India

4. Write true or false:

1. Nuclear reactor is based on the concept that a slow moving neutron splits uranium.
Answer:
True

2. Mesons were discovered by Clark David Anderson.
Answer:
False

3. Newton had given the corposcular theory of light.
Answer:
True

4. Tn 1921, Albert Einstein got the noble prize for theory of relativity.
Answer:
False

5. Fast moving particles are studied using the theory of relativity.
Answer:
True

MP Board Class 11th Physics Important Questions Chapter 1 Physical World

5. Answer in one word:

1. What is Einsteins mass energy equivalence equation?
Answer:
E = mc2

2. Substance which has mass is called?
Answer:
Matter

3. Rocket propulsion is based on which law?
Answer:
Newton’s third law of motion

4. The laws of photoelectric effect is explained by which equation?
Answer:
Einsteins photoelectric of equation

5. Who gave the principle of uncertainty?
Answer:
Heisenberg (Germany)

MP Board Class 11th Physics Important Questions

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